16 results about "Background fluorescence" patented technology

The application discloses a double-line ratio fluorescent competitive immunochromatographic detection device and a preparation method and application thereof, and relates to the technical field of immunochromatographic detection.The detection device comprises a double-specificity recognition unit mixed-labeled quenched fluorescent probe, a background fluorescent material and a solid phase substrate, the solid phase substrate is provided with a T line on which a target object binding ligand is immobilized and a C line on which a quality control ligand is immobilized; and the application also provides application of the detection device in detection of exogenous harmful substances.The application solves the technical problem of low detection sensitivity of the existing method, and adjusts the binding amount of the probe on the T line and the C line through an immune competition reaction, adjusts the quenching degree of the background fluorescence based on an internal filter effect, takes (T line quenched fluorescent signal / background fluorescent signal) / (C line quenched fluorescent signal / background fluorescent signal) as a quantitative signal, and takes the C line to participate in ratio calculation to improve the detection sensitivity, so that the application is suitable for high-sensitivity qualitative and quantitative detection of small molecule compounds and the detection sensitivity is improved.

This invention discloses a multi-stimulus-responsive upconversion luminescent nanocrystalline magnetic microsphere and its preparation method, belonging to the field of biomedical polymer materials and nanobiotechnology. The microsphere's main body is a porous copolymer matrix, encapsulating a core of magnetite (Fe3O4) magnetic nanocrystals. Rare-earth-doped fluoride upconversion luminescent nanocrystals are coupled to the surface and pores. The copolymer side chains of the microsphere incorporate azide groups, acidic stimulus-responsive groups, and photostimulation-responsive groups, constructing an independent and non-interfering triple orthogonal logic gating system on the surface. The preparation method includes preparing an oil phase containing copolymers, magnetic nanoparticles, and a volatile porogen; pre-emulsifying and homogenizing the oil phase in an acidic aqueous phase using an SPG membrane; inducing phase separation by controlled solvent evaporation to form porous microspheres; and finally coupling the upconversion nanocrystals via a click chemistry reaction. The magnetic microspheres of this invention eliminate background fluorescence interference from complex samples from a physical perspective. Their porous structure endows the microspheres with excellent quasi-levitation properties and magnetic responsiveness, effectively solving problems such as single surface function and signal crosstalk of microspheres. They are suitable for in vitro clinical diagnosis and complex analysis of multiple targets.

This invention belongs to the fields of biomedicine and fluorescent probe technology, and relates to a biheaded functional molecule and its application in the preparation of products for imaging cell tailpods or migration bodies. The biheaded functional molecule has the chemical structure shown in Formula I; wherein R is a hydrophilic positive ionic fluorescent group, X is methylene or O, Y is methylene or carbonyl, and n is 1~3. The biheaded functional molecule provided by this invention can achieve long-term cell membrane anchoring and can dynamically track the migration body formation process with low phototoxicity, low background fluorescence, high photostability, and high brightness.

The present application relates to the technical field of bacillus subtilis secretion preparation, and discloses a preparation method of a composition containing bacillus subtilis secretion, comprising: physically splitting a sampling flow through a cross-flow filtration module in a sampling period to obtain a first test branch fluid and a second test branch fluid; injecting a fluorescence resonance energy transfer probe into each branch fluid to obtain an enzymatic kinetic signal, determining a kinetic parameter of each branch and calculating a ratio value, providing a preparation trigger instruction based on the ratio value evolution trend, and adding a stabilizer or extracting the composition according to the instruction. The present application uses in-situ two-phase kinetic ratio test logic to decouple the relative distribution of free state activity and attached state activity, offsets background fluorescence noise and sampling fluctuation, solves the determination contradiction between the physical release amount of the secretion and the protein self-degradation effect, and establishes a robustness scale of the composition preparation timing.

The present application relates to the field of new material detection, and discloses a kind of surface opening defect fluorescence imaging nondestructive evaluation process, comprising: determining the permeation process parameter, flushing the surface of the workpiece to be measured and real-time collection fluorescence radiation intensity, according to the slope of the change of fluorescence intensity with the change of washing time to determine the washing stop timing, monitor the dynamic growth of fluorescence radiation intensity after applying developer, when the intensity growth meets the preset stability criterion continuously, determine the exudation stable state and generate a trigger signal, open white light environment to identify defects, the evaluation driving force is reconstructed from the conventional clock cycle to the interface physical state evolution, the equilibrium characteristics of the elution of penetrant and capillary exudation kinetics are used to capture the process inflection point, the background fluorescence interference is inhibited and the defect signal is retained, the defect miss detection and halo contradiction produced by fixed time limit are eliminated, and the physical reproducibility of large batch workpiece detection is improved.

This invention relates to a method for regulating zirconium-based metal-organic framework nanoparticles using carboxylated cellulose nanoparticles. This method utilizes carboxylated cellulose nanoparticles, a green and environmentally friendly material, as a defect modulator, and obtains UiO-66-OH with tunable defect levels via an in-situ one-pot synthesis. Using carboxylated nanoparticles as a nano-soft template, carboxyl competitive ligands, and surface-assisted growth medium, the method induces the heterogeneous nucleation and explosive growth of UiO-66-OH crystals into nanospheres. Precise defect regulation is achieved through the precise competitive coordination of carboxyl groups and zirconium ions. While achieving defect regulation and ensuring stability, background fluorescence is modulated through the disruption of intramolecular charge transfer (ICT). This provides a solid research foundation for the regulation of defective metal-organic framework materials and their bio-friendly applications.

The application provides a tongue feature intelligent recognition method and system, relates to the technical field of biomedical detection, and is characterized in that after obtaining a preprocessed original composite light signal, fixed-frequency environmental light interference is accurately identified and removed through fast Fourier transform analysis, and confusion of environmental noise on subsequent signal processing is avoided.When the target tongue surface area is displaced to cause dynamic changes of background fluorescence signals, a preset adaptive filtering algorithm can accurately identify and remove the changed tongue image background fluorescence digital signal values in real time.This step-by-step and adaptive processing strategy ensures that the removal of environmental light interference and the correction of background fluorescence signals are independent and do not interfere with each other, thereby avoiding the generation of internal processing conflicts and calculation artifacts described in the background technology, and obtaining highly pure and accurate tongue image fluorescence digital signals, significantly improving the accuracy and reliability of tongue feature recognition, and providing a more reliable data basis for oral health detection.

This invention discloses a method for site-specific fluorescent labeling of proteins in cell lysates and its applications, belonging to the field of pharmaceutical bioengineering technology. Utilizing genetic code amplification technology, non-natural amino acids containing azide groups are introduced at specific sites of the target protein. A long-lifetime terbium complex modified with dibenzocyclooctylene is directly added to the cell lysate, enabling copper-free click chemistry labeling of the target protein. This method exhibits good biocompatibility and wide applicability, and can construct CoraFluor-DBCO-labeled protein target libraries. Furthermore, a time-resolved fluorescence resonance energy transfer (TR-FRET) screening system is constructed, utilizing the long fluorescence lifetime of the terbium complex to filter out biological background fluorescence and improve the signal-to-noise ratio. Competitive TR-FRET enables homogeneous screening of small molecule ligands targeting the target protein in the lysate. This method avoids protein purification steps, is simple to operate, and has high screening efficiency.

The application provides a dye for constructing a high-sensitivity long-wavelength fluorescent probe and a preparation method thereof, the fluorescent dye parent body is a rhodol dye, a structural formula of the rhodol dye is shown as formula A: formula A is connected with any one of the following structural formulas; wherein R1 is one of H, C1-20 alkyl and a benzene ring; R2 is one of H, F, Cl, Br and I; R3 is one of (n=0-20); R4 is one of (n=0-20). The rhodol dye covers a spectral range of 500-750 nm, is almost completely in an open ring state under physiological conditions, and is completely converted into a non-fluorescent spiro ring state by adopting a methyl or a response site shielding hydroxyl, therefore, the probe constructed based on the dye has extremely low self-background fluorescence; along with activation of the probe, the shielding hydroxyl is gradually released, the non-fluorescent probe is converted into a strong fluorescent dye, thereby the probe is endowed with a significantly improved response activation multiple and extremely high response sensitivity.

Disclosed is a fluorescent probe for glucose oxidase β The application discloses a kind of with big stokes shift The structure of the fluorescent probe QM-GLU is shown as formula I.The QM-GLU has almost no fluorescence at 560 nm when excited by a 450 nm wavelength, but can selectively undergo a fluorescence opening reaction with GLU.The fluorescence intensity at 560 nm gradually increases with the increase of GLU concentration, and other common interfering substances do not significantly interfere with the detection of GLU by QM-GLU and have no effect.Due to the characteristics of its AIE mechanism, and has a large stokes shift (110 nm), which greatly reduces the interference of system background fluorescence and improves the sensitivity of GLU activity detection.Therefore, QM-GLU is suitable for high selectivity and high sensitivity fluorescence detection of GLU.

This invention discloses an "on-off" type butyrylcholinesterase near-infrared fluorescent probe, its preparation method, and its applications. The structural formula of the fluorescent probe QCL-BChE is shown in Formula I. When excited at a wavelength of 720 nm, QCL-BChE shows almost no fluorescence emission at 765 nm. When QCL-BChE coexists with BChE, a significant fluorescence emission peak appears at 765 nm. As the concentration of BChE increases, the fluorescence intensity at 765 nm gradually increases, and other common interfering ions, substances, and enzyme species do not significantly interfere with or affect the detection of BChE. Because the emission wavelength is in the near-infrared region, the interference of system background fluorescence is greatly reduced, improving the sensitivity for detecting BChE activity. In addition, QCL-BChE has been successfully applied to the fluorescence imaging of endogenous BChE in LO2 cells and HepG2 cells.

The application discloses a ratio type near-infrared fluorescent probe based on an ICT-FRET mechanism and a preparation method and application thereof. The ratio type near-infrared fluorescent probe based on the ICT-FRET mechanism emits in a near-infrared region, has an ultra-large stokes shift, can effectively avoid excitation light interference and self-absorption, reduces biological background fluorescence, and is suitable for deep tissue imaging. The probe can realize double-emission ratio response (I 660 / I 540 ) based on the FRET mechanism, has a significant signal change, has inherent self-calibration capability, shows extremely high selectivity to Cys, has almost no response to Hcy and GSH similar in structure, is strong in anti-environmental interference, and is more accurate in quantification. The TPP targeting group of the probe enables the probe to be specifically positioned in mitochondria of living cells, realizes dynamic ratio imaging of endogenous and exogenous Cys in mitochondria, and provides a powerful tool for studying Cys metabolism at a subcellular level.

This invention discloses a fluorescence detection microfluidic chip and its fabrication method. The fluorescence detection microfluidic chip includes a first film layer and a second film layer. The first film layer includes a main layer and multiple elongated protrusions. The main layer, two adjacent elongated protrusions, and the second film layer together form a microchannel. The main layer, the elongated protrusions, and the second film layer are all made of polytetrafluoroethylene (PTFE). In the fluorescence detection microfluidic chip of this invention, the refractive index of PTFE (1.29) is lower than that of water (1.33), thus allowing the relatively high refractive index of the sample to be tested to form a liquid optical waveguide, confining the light field within the microchannel. This effectively delivers the sample while maximizing the interaction between light and the analyte, thereby effectively reducing the background fluorescence noise generated by the material itself and improving detection sensitivity. It can be used to construct a high-sensitivity fluorescence detection system.

The application discloses a kind of 5-fluorouracil reaction liquid monitoring and rectification purification method, it is related to 5-fluorouracil reaction liquid technical field.Formation contains original multidimensional Raman spectrum data set of time sequence characteristics;Extract the characteristic absorption peak array of eliminating background fluorescence interference;Mapping out the real-time concentration distribution sequence of 5-fluorouracil main body, unreacted precursor and by-product impurities in reaction liquid;Calculate dynamic thermodynamic phase equilibrium offset, and construct adaptive rectification control strategy;Get primary concentrated reaction liquid;Realize the deep separation of recombination impurities, and collect high-purity 5-fluorouracil rectification liquid;Build multivariate prediction error loss function, and form reaction-rectification closed-loop monitoring and purification control network to adaptive rectification, the application makes when processing extremely heat-sensitive degradation pharmaceutical intermediates, the real yield of target product is significantly improved, especially in multi-component azeotrope region performance is particularly outstanding.

This invention belongs to the field of laser Raman technology, specifically a surface-enhanced Raman (SMR) substrate and its preparation method. The SMR substrate of this invention comprises, from bottom to top, a substrate, a silicon dioxide layer, a hafnium sulfide layer, and a two-dimensional material layer. A heterostructure is constructed using hafnium sulfide nanosheets and two-dimensional material nanosheets as the SMR substrate. Probe molecules for Raman detection can be attached to the upper surface of the two-dimensional material layer. This substrate enhances the Raman signal of the probe molecules through the unique multi-order optical interference constructive phase of hafnium sulfide and the charge transfer mechanism between the two-dimensional material and the probe molecules, thereby enhancing the SMR effect of the two-dimensional material. The preparation method of this invention is simple, low-cost, and highly efficient. The substrate material provides significant Raman enhancement, high sensitivity, and low background fluorescence, and does not form chemical bonds with the probe molecules, effectively improving measurement accuracy and showing broad application prospects.